<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #d1{
            width: 100px;height: 100px;border: 1px solid red;
           /* margin-bottom: 100px;*/
            margin: 10px 20px 30px 40px;
        }
        body{margin: 0}
        #d2{
            width: 100px;height: 100px;border: 1px solid red;
            /*上下相邻彼此添加边距取最大值*/
            margin-top: 100px;
        }
        #s1{
            /*行内元素上下外边距无效*/
           /* margin-bottom: 100px;*/
            margin-right: 100px;
        }
        #s2{
            margin-left: 50px;
        }
        #big{
            width: 200px;
            height: 200px;
            background-color: red;
        }
        #big>div{
            width: 50px;
            height: 50px;
            background-color: green;
            margin-left: 50px;
            margin-top: 50px;
        }
    </style>
</head>
<body>
<div id="big">
    <div></div>
</div>
<span id="s1">span1</span>
<span id="s2">span2</span>
<div id="d1"></div>
<div id="d2"></div>
</body>
</html>